One vertex per element, one color per generator, with an edge from x to x·s.
(1,2)(3,5)(4,6)(7,8)(9,10)(11,19)(12,16)(13,17)(14,18)(15,21)(20,24)(22,23)(25,26,30,34)(27,35,38,31)(28,39,42,48)(29,43,46,33)(32,40,50,36)(37,47,44,51)(41,56,45,55)(49,53,52,54)(1,3)(2,5)(4,7)(6,8)(9,11)(10,15)(12,20)(13,22)(14,21)(16,23)(17,24)(18,19)(25,27,30,38)(26,31,34,35)(28,40,42,36)(29,44,46,37)(32,48,50,39)(33,51,43,47)(41,53,45,54)(49,55,52,56)(2,6)(3,7)(9,12,14,13)(10,16,18,17)(11,20,21,22)(15,23,19,24)(25,28,27,36,30,42,38,40)(26,32,31,39,34,50,35,48)(29,45,37,54,46,41,44,53)(33,52,47,56,43,49,51,55)(9,12,14,13)(10,17,18,16)(11,20,21,22)(15,24,19,23)(25,29,30,46)(26,33,34,43)(27,37,38,44)(28,41,42,45)(31,47,35,51)(32,49,50,52)(36,53,40,54)(39,55,48,56)(3,7)(5,8)(9,13,14,12)(10,17,18,16)(11,20,21,22)(15,23,19,24)(29,46)(33,43)(37,44)(41,45)(47,51)(49,52)(53,54)(55,56)A Cayley diagram is a choice, not a fact about the group. Another drawing of this group — in a book, or on a different generating set — may look nothing like this one.